Current efforts on this project are directed at: 1. Determining the sequence of "glutamate" and "cysteine" tryptic and chymotrytic peptides (to provide sequence overlap) in the low- and high-salt conformers, respectively of BrPyv inactivated KDPG aldolase from Ps. putida. 2. Identifying which cyanogen bromide cleaved fragment of BrPyv inactivated KDPG aldolase contains the reagent-sensitive glutamate and cysteine. 3. Identifying the BrPyv-sensitive amino acid in KDPG and KDPGal aldolases of Ps. saccharophila. 4. Determining whether BrPyv is a cross-linking reagent for each enzyme, i.e., bridging between the BrPyv-sensitive amino acid and the catalytically functional lysine. Further purification of commercially available NAN-aldolase to study its interaction with tritiated halopyruvates. BIBLIOGRAPHIC REFERENCES: An enzymatic synthesis yielding crystalline sodium pyruvate labeled with isotopic hydrogen. Meloche, H.P. Methods in Enzymol. 41:106 (1975). The interaction of bromopyruvate with the active site of 2-keto-3-deoxy-6-P-galactonate aldolase. Kinetics and stereochemistry. Meloche, H.P., and Monti, C.T. Biochem. 14:3682 (1975).